A liquid crystal display is a kind of a flat type display. The use of a liquid crystal display is increasing as a solution to shortcomings of a cathode ray tube (abbreviated to CRT), a typical conventional electric display, that is, the depth and the weight. At the beginning, a liquid crystal display was a monochrome display, but the full colorization of a liquid crystal display was an inevitable request because a CRT has been providing a full color display for a long time.
A conventional liquid crystal color display was mainly used for office equipments such as a word processor and personal computer which displays letters, graphics, charts, tables, and the like in color. For the conventional display, a color purity of the 3 primary colors of red, green, and blue will be improved if the value of the film thickness of a color filter or the concentration of a pigment is made higher, but to the contrary, a transmittance of a color filter will decrease causing a dark display image. Therefore, for a liquid crystal display for a note type personal computer, the transmittance was thought to be more important than the color purity to obtain brighter display with a low electric power consumption light source so that the driving hour of a battery is made longer.
However, a wide use of a fixed type liquid crystal display demands a color purity of a CRT level. Moreover, a possibility of an animation display with a liquid crystal display with the advance of technology demands a high color purity of red, green, and blue, and a high color reproduction of a half tone display including flesh color. Therefore, for an example, a light source with a narrow band spectral property is used for a light source of a liquid crystal color display. The peak wavelength of the light source and the peak wavelength of the transmitting wavelength band of each color filter element are almost coincided so that an excellent color reproduction property is obtained by increasing the color purity of a liquid crystal color display (Japanese Patent Application Laid-open No. 7-253577, and No. 7-261167).